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A novel member of the YchN‐like fold: Solution structure of the hypothetical protein Tm0979 from Thermotoga maritima
Author(s) -
Gaspar Joe A.,
Liu Chengsong,
Vassall Kenrick A.,
Meglei Gabriela,
Stephen Ricardo,
Stathopulos Peter B.,
PinedaLucena Antonio,
Wu Bin,
Yee Adelinda,
Arrowsmith Cheryl H.,
Meiering Elizabeth M.
Publication year - 2005
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.041068605
Subject(s) - thermotoga maritima , fold (higher order function) , protein structure , protein quaternary structure , structural genomics , protein secondary structure , crystallography , beta sheet , chemistry , protein folding , protein structure prediction , biology , biochemistry , protein subunit , escherichia coli , gene , mechanical engineering , engineering
We report herein the NMR structure of Tm0979, a structural proteomics target from Thermotoga maritima . The Tm0979 fold consists of four β/α units, which form a central parallel β‐sheet with strand order 1234. The first three helices pack toward one face of the sheet and the fourth helix packs against the other face. The protein forms a dimer by adjacent parallel packing of the fourth helices sandwiched between the two β‐sheets. This fold is very interesting from several points of view. First, it represents the first structure determination for the DsrH family of conserved hypothetical proteins, which are involved in oxidation of intracellular sulfur but have no defined molecular function. Based on structure and sequence analysis, possible functions are discussed. Second, the fold of Tm0979 most closely resembles YchN‐like folds; however the proteins that adopt these folds differ in secondary structural elements and quaternary structure. Comparison of these proteins provides insight into possible mechanisms of evolution of quaternary structure through a simple mechanism of hydrophobicity‐changing mutations of one or two residues. Third, the Tm0979 fold is found to be similar to flavodoxin‐like folds and β/α barrel proteins, and may provide a link between these very abundant folds and putative ancestral half‐barrel proteins.